The invention relates to a structural material and more particularly relates to a composite using multiple component materials to fabricate the resulting structural material.
In the past, several techniques have been used to produce materials useful in providing a rigid or semirigid wall, housing, or other structural piece. These techniques have included the making of structural sections from sheet metal, or from casting plastics, or from using any other material that would give the best combination of strength and weight for a given structural use. Since very few single materials are exceptionally versatile, it became natural to combine different materials into structural composites in order to combine the most desirable qualities of each type of material in the composite. Examples of some materials that could be combined into composites were screens made out of metals or plastics, woven textile fabrics, resins that would harden after they had been cured, plastic films and sheets, layers of various metals of various thicknesses, or different types of foams that would harden and become rigid when they cured. These different types of structural materials would be held together either by embedding, by adhesives, or by some kind of mechanical means, such as by stapling or tacking.
In many applications, there arises a need for a structural material that is capable of being set against a selected contour or shape, and which will then permanently retain that contour or that shape. A simple example is that of pressing a sheet of heated plastic against the surface of a mold. However, a single structural material, such as a sheet of plastic, is not versatile enough to meet many of the structural or electrical requirements of different applications. Therefore, there is a need for a structural composite made up of different materials, which is capable of being moldable or conformable, and yet has more versatility in the end-product uses to which it can be put than ordinary conformable materials alone.
Many specific attempts at meeting this need have been tried. In general, composites contain two or more distinct ("distinct" here meaning formulated from a distinct manufacturing process) materials as a unified combination. Thus, efforts have included embedding multifiber or wire substrates into a reinforcing matrix. In another approach, fiberglass cloth has been mixed with a resin, the mixture applied over a metallic screen, and then more resin applied over the entire composite, and allowed to solidify. Alternatively, a thin sheet of metal would be adhered or affixed to a plastic mounting plate, having a hollow section that could then be filled out with a foam or another suitable resin. Another approach was to prepare a batt of nonwoven fiber of a synthetic resin, which would soften when subjected to heat and then tack this batt onto a metallic foil to form a panel, which would then have a tar or adhesive applied to the outside of the panel. Still another approach was to take a resin that would harden upon curing, but to add glass fibers to the resin before it did cure and harden. The common element in all these approaches is that a matrix contains a reinforcement.
These approaches had many shortcomings. The method of production would be too expensive, or the materials used in the composite would be too expensive, or the final product might not be rigid enough or strong enough as a structural material. Also, the composite might not be capable of being molded or conformed to certain specific desired shapes, or the composite might not be lightweight enough for a given application. A related concern arises in the field of electronics, where it is frequently desirable to have a structural material that has a metallic portion in order to act as a shield or as a reflector, depending on the given application. A desirable material, therefore, should be relatively inexpensive, lightweight, strong, be capable of being molded or conformed to desirable shapes, and in certain electronic applications, have a metallic component. The reinforcing component also should have a high ratio of length to diameter (aspect ratio), should be stronger than the matrix, should have a higher modulus of elasticity, and should readily form a bond with the material of the matrix. The present invention overcomes prior shortcomings and meets these needs.
It is an object of the present invention to provide a versatile structural material, which can be used in a wide variety of structural applications. It is a further object of the invention to provide a structural material, which can be used in electronic applications. It is a further object of this invention to provide a material that can be used in electronic applications as a shield or as a reflector. It is yet a further object of this invention to provide a material that can be used to attenuate radioactive emissions. It is still a further object of this invention to provide a material capable of being moldable or conformable to a wide variety of different shapes and sizes, without tearing or breaking during the production process. Other objects of this invention are to provide a structural material, which is lightweight, sufficiently strong in relation to its weight, and sufficiently inexpensive to manufacture in relation to its weight and its strength.
This invention features a reinforcing substrate of textile fibers that can readily have attached to them a variety of different metallic or nonmetallic foils, which can be molded or conformed against a given shape using heat molding techniques, and which can be rigidified by embedding it in a suitable resin, foam, or adhesive.
An advantage of this invention is that a metallic or nonmetallic foil can be attached to a fibrous reinforcing substrate to produce a foil-substrate composite, which can be drawn or shaped without tearing the foil. Another advantage is that when suitable heat-moldable or thermoplastic textile fibers are used for the substrate, the foil-substrate composite can be heat molded to a wide variety of desired shapes. Another advantage of this invention is the ability to use and incorporate a metallic layer in a structural material, particularly for various electronics applications. A further advantage of this invention is the ability to rigidify the foil-substrate composite to provide a high degree of strength in relation to the composite's weight. Yet another advantage of this invention is the ability to incorporate a suitable metal for the shielding of radioactive emissions. It is yet another advantage of this invention that a given version of the foil-substrate composite can be mass produced, thereby making it more economical to manufacture.